implement event persistence and improve Mongoose TypeScript patterns

- Add event persistence: confirmed events are now saved to MongoDB
- Refactor Mongoose models to use virtuals for id field with IdVirtual interface
- Update repositories to use toJSON() with consistent type casting
- Add more test responses for chat (doctor, birthday, gym, etc.)
- Show event description in ProposedEventCard
- Change mongo-express port to 8083
- Update CLAUDE.md with Mongoose model pattern documentation

apps/server/src/controllers/ChatController.ts

@@ -1,5 +1,5 @@
 import { Response } from 'express';
-import { SendMessageDTO } from '@caldav/shared';
+import { SendMessageDTO, CreateEventDTO } from '@caldav/shared';
 import { ChatService } from '../services';
 import { AuthenticatedRequest } from '../middleware';
 
@@ -21,7 +21,8 @@ export class ChatController {
     try {
       const userId = req.user!.userId;
       const { conversationId, messageId } = req.params;
-      const response = await this.chatService.confirmEvent(userId, conversationId, messageId);
+      const event: CreateEventDTO = req.body;
+      const response = await this.chatService.confirmEvent(userId, conversationId, messageId, event);
       res.json(response);
     } catch (error) {
       res.status(500).json({ error: 'Failed to confirm event' });